1. Field of the Invention
The present invention relates to a CMOS image sensor (CIS) system, and more particularly, to a signal processing circuit of the CIS system which is capable of improving the dynamic range of the output signal with high processing speed.
2. Description of the Prior Art
In a conventional CMOS image sensor (CIS) system, the dynamic range of the output signal is excessively restricted. For enhancing the dynamic range of the output signal of the CIS system to achieve high dynamic range (HDR), an existing solution is to provide longer exposure time for darker signal and to provide shorter exposure time for brighter signal. Besides, another existing solution is to augment the resolution of the ADC of the CIS system. However, employing the conventional solutions mentioned above inevitably increases the product cost.
Moreover, the existing manners for enlarging the dynamic range of the CIS system are time-wasting and require high circuit complexity. There is a demand for providing a novel signal processing method and signal processing circuit to enhance the dynamic range of the output signal to thereby promote the performance of the CIS system without greatly increasing the product cost.